Timing device



A. B. FULLER TIMING DEVICE March 14, 1939.

Filed 001; 7, 1956 Albert B. Fuller INVENTOR. $9 a! Patented Mar. 14,1939 TIMING DEVICE Albert B. Fullen, Rochester, N. Y., assignor toEastman Kodak Company, Rochester, N. Y., a corporation of New JerseyApplication October '7,

2 Claims.

This invention relates to. timing devices, more particularly it relatesto ratchet relays for use in timing devices.

It is an object of this invention to provide a simple and dependableratchet system which will transform a plurality of impulses into one ormore revolutions of a wheel.

It is a particular object of this invention to provide a positive actionratchet pull-down which will rotate a ratchet wheel one tooth or aspecified number of teeth at a time.

Other objects and advantages of this invention will be apparent from theaccompanying drawing in which:

Figure l is a perspective view of a device typical of this invention andillustrates the principle thereof.

Figures 2, 3, 4, and 5 are different views of one particular form ofthis. invention. Figure 2 is a front elevation; Figure 3 is a sideelevation; Figure 4 is a rear elevation; Figure 5 is a plan.

For clarity, I shall use the terms, horizontal and vertical to describethe relative orientation of the various members of the mechanism of thisinvention. However, it is to be understood that these terms are merelyrelative and do not necessarily refer to the actual orientation inspace.

In Figure 1, a ratchet wheel Ii, having teeth, Ila, lib, Ilc, etc., ispropelled, one tooth at a time, by the end 26 of a bar ll which issubstantially horizontal and perpendicular to the plane of the ratchetwheel II. This bar H is pivotally mounted on a support 2G by a pivot 2|!so that the bar ll itself is free to rotate in a horizontal plane. Thissupport 28 is provided with a restraining member 24 which insures thatthere will be practically no vertical rotation of the bar I! relativethereto. Pressure exerted downward on the support 28 is thus transmittedby the member 24 to the bar l1. Furthermore, the support 20 is mountedon a base, not shown in this figure, and is hinged along the line 25 sothat it to a slight degree, free to rotate in a vertical plane. Thus,the end 26 of the bar ii is permitted both vertical and horizontalmovements, and the bar l'l may be considered to be attached through auniversal joint to the base mentioned above. These vertical andhorizontal movements are confined within the limits defined by twoL-shaped members it! and it, which are rigidly mounted with respect tothe base and the axis of the ratchet wheel II. A spring 23 which ismounted diagonally in a vertical plane provides tension on the bar I! sothat the end 26 is urged upward and toward the 'ra chet wheel ll. This1936, Serial No. 104,561 (01. 74-142) spring 23 is equivalent to twosprings, one verti-- cal and one horizontal, and may be replaced by anysuitable arrangement which will provide a positive tension having ahorizontal and a vertical component.

To operate the device, pressure is exerted downward either directly onthe bar I! or on the support 20 which carries the bar IT. This causesthe end 26 of the bar I! to move downward inengagement with the backface of the tooth Ila 10 until the bar ll strikes the horizontal portionof the confining member l8. Simultaneously the bar 57 is caused to movelaterally by the front face of the next tooth Nb of the ratchet wheel II so that it strikes or is very close to the upright 16 portion of theconfining member l8 at the same time that it strikes the horizontalportion of the confining member l8. In this final position, theratchetwheel H is unable to rotate in either direction and, hence, cannotovershoot so that 20 it rotates more than one tooth at a time. A detent(not shown in this figure) prevents the ratchet wheel ll rotating in theopposite direction when the pressure onv the bar ii is released. I

When this pressure is released the spring 23 25 causes the end 26 of thebar ll to move upward until it strikes the horizontal portion of theconfining member !9, and horizontally until it strikes the verticalportion of the confining member 19 or the next tooth lie of the ratchetWheel H. 30;

The vertical portion of the confining member i9 is not essential to thisinvention. The end 26. of the bar I! is now in the primary position inits cycle and is ready to engage the next toothllb of the ratchet wheelll. Careful positioning 35, of the confining members 18 and I9 insuresthat the action through this cycle as. described is positive. i. e. thatsuitable consecutive impulses to the support 29 or directly to the barI! will invariably cause the end 26 to engage conse- 40 cutive teeth ofthe ratchet wheel I l.

Under some circumstances it may be desirable to have the ratchet wheelmove two or any predetermined number of teeth for each impulse received.This may be accomplished by suitable 45 arrangement of the confiningmembers 18 and I9. Figure 2 shows a particular arrangement of the deviceshown in Figure 1. A ratchet wheel II is mounted to rotate in a verticalplane on an axle l2 which is mounted on a vertical plate is which 50v inturn is parallel to the plane of the ratchet wheel I! A detent I l isprovided to prevent the ratchet wheel ll rotating counter-clockwise asviewed. The detent I4 is pivoted at the point l5 and isheld in contactwith the-ratchet wheer H: 55;

by a spring IS in a well known manner. The end 26 of the bar I? is shownengaging one of the teeth of the ratchet wheel I l. The confiningmembers l8 and Hi described in connection with Figure 1 are rigidlyattached to the vertical plate I3 which is provided with a circular holethrough which the bar I! projects. The confining member I8 is mounted onthe front face of the plate, 13 and the confining member i9 is mountedon the rear face of this plate it.

Figure 3 shows a side elevation of the particular arrangement of theinvention whose front elevation is shown in Figure 2. Similar referencenumerals refer to similar elements in all of the drawings. In additionto the parts shown in Figure 2, Figure 3 also shows a support 20 uponwhich the bar I7 is pivotally mounted by a pivot 2!. The support 20 ishingedly mounted, at the point 25, to a base 22 to which the verticalplate 13 is rigidly attached. One end of a spring 23 is attached to thebar H as described in connection with Figure 1. The other end isattached at the point 27 to the base 22.

The impulses affecting the bar H may be of various types depending ontheir origin. In Figure 3 an electromagnet 30 provides a convenientmethod of transforming electrical impulses into mechanical impulsesthrough the support 20 which constitutes the armature of theelectromagnet 39.

Referring to Figure 4 which is a rear elevation of the device shown inFigures 2 and 3, one will see that the spring 23 is mounted with itsaxis diagonal in a vertical plane and is fastened at one end to the bari1 and at the other end to the base 22 at the point 27.

Figure 5 is a plan or top view of the device shown in Figures 2, 3 and4; Since similar reference numerals refer to similar parts of thedevice,

a detailed description of this figure would be relay in the mannerdescribed and also the important features of my invention will be moreclearly understood from the following discussion of the principleunderlying its operation.

I have found that an ideal ratchet wheel system is one in which theteeth are symmetrical, have a right angle vertex, and are arranged sothat their front and back faces are inclined at an angle of 45 degreesto the adjacent radii of the wheel. For practical purposes any of theradii which intersect a particular tooth may be considered as beingadjacent to that tooth since all such radii are within a few degrees ofbeing parallel. Also in this ideal system, the impulse provided by theadvancing movement of the propelling member is entirely perpendicular tothe back face of the tooth being engaged and parallel to the front faceof the next tooth. Furthermore, the return movement of the propellingmember must have no lateral component away from the ratchet wheel.

I have also found that most of the advantages of this ideal system canbe realized with a modification thereof such as that described in detailabove and shown in the accompanying drawing. This arrangement is, atpresent, more convenient to manufacture than one according to the idealsystem would be and it has the added advantage of permitting evengreater tolerance to manufacturing errors than the idealsystem. It willbe noted that this modification follows the ideal system, firstly, inthat the front faces of the teeth are inclined to the radii of theratchet wheel at an angle substantially equal to or greater than 45degrees,

secondly, in that the impulse provided by the propelling member is alsoat an angle of 45 degrees to the wheel radii, i. e., parallel to thefront faces of the teeth and, thirdly, in that the return movement ofthe propelling member has no lateral component away from the ratchetwheel. Such a component would probaly be due to the front face of the.next tooth to be engaged and would cause considerably increased frictionwith this face.

. It has been customary prior to my invention to Jarrange the engagementbetween the teeth and the propelling member of a ratchet wheel system sothat the impulse provided thereby is as nearly tangential to the wheelcircumference as possible, so as to permit a maximum leverage about thecenter of the wheel and to minimize any component of force toward thecenter of the wheel. According to my invention, this impulse should beat an angleito the adjacent radii equal to or less than 45 degrees, ormore exactly, equal to or less than the angle between this radius andthe front face of the next tooth. The best results are obtained when thepropelling impulse and the front face of the tooth are substantiallyparallel and inclined to the adjacent radius at an angle approximatelyequal to or slightly greater than 45 degrees.

Among the advantages gained by the use of my invention is the'fact thatthe apparatus may be assembled in a relatively loose manner without lossof ability to operate positively. In the drawing, this relativelooseness of adjustment is quite apparent from the simple manner .inwhich the support 26 is hinged about the line 25, namely. by being heldby two hook-shaped knobs on the face 22 which fit loosely into two holesin the support 28 as shown. Furthermore, a ratchet wheel systemconstructed according to the drawing is inexpensive to manufacture andrelatively compact in form. .It may be employed wherever these factorsare of major importance.

Other arrangements of this invention will suggest themselves to thoseskilled in the art. Although for the sake of clarity, I have shown anddescribed only one particular form of my invention, I wish to point outthat it is not limited to the specific structure shown but is of thescope of the appended claims. For definiteness in the claims the termadjacent radius will be taken to mean the radius through the top of thetooth, but obviously such a definition is more critical than theinvention requires.

What I claim as my invention and wish to secure by Letters Patent of theUnited States is:

1. In a ratchet relay assembly, the combination with a ratchet wheelhaving a plurality of teeth, a detent so mounted that rotation of saidratchet wheel is confined to one direction, a propelling member mountedperpendicular to said ratchet wheel for; engagement with the teeththereof, mounting means movably supporting said propelling member andpermitting advancing movement thereof to advance said ratchet wheel, andpermitting return movement thereof out of engagement with one tooth ofsaid ratchet wheel into position to engage another tooth of said ratchetwheel, said mounting means also permitting lateral movement of saidpropelling member with respect to said ratchet wheel, a resilient meansconnected to said propelling member for :returning the same afteradvancing movement thereof and for laterally urging the same intoengagement with the teeth of said ratchet wheel,

means for actuating said propelling member to advance said ratchetwheel, two guide members on opposite sides of said propelling memberand. for limiting the advancing and return movements thereof and a thirdguide member positioned near said propelling member to limit the lateralcomponent of its advancing movement so that said propelling member inits most advanced position prevents advancing movement of said ratchetwheel.

2. In a ratchet relay assembly, the combination with a ratchet Wheel, apropelling member mounted perpendicular to said ratchet wheel forperpendicular lateral engagement with the teeth thereof, mounting meansmovably supporting said propelling member and permitting movementthereof to advance said ratchet wheel, a resilient means connected tosaid propelling member for returning the same after advancing movementthereof and for urging the same into engagement with said ratchet wheeland guide members so mounted that the advance and return movements ofsaid propelling member are limited thereby.

ALBERT B. FULLER.

